The suspected killer published a 74-page manifesto that referenced Trump, saying he supported Trump as a symbol of “renewed white identity” but not as “a policy maker and leader.”

CAIR, the largest Muslim advocacy organization in the U.S., warned against blaming any one person for the shooter’s actions, but pointed to research showing a rise in anti-Muslim sentiment since Trump was elected. CAIR National Executive Director Nihad Awad said Trump needs to assure Muslims that they are protected and that he will not tolerate violence against their community.

“Mr. Trump, your words matter. Your policies matter. They impact the lives of innocent people at home and globally,” Awad said at a news conference Friday.

Trump said on Twitter that he stands by New Zealand and offered his sympathy to those who “senselessly died.” White House spokesperson Sarah Sanders also said in a statement that the U.S. “strongly condemns the attack.”

The events have been widely condemned by leaders across the globe.

The Organization of International Cooperation, the world’s largest organization representing Muslim nations, said the attacks should serve as a warning of “the obvious dangers of hate, intolerance and Islamophobia.”

CAIR noted that there are 3,000 mosques in the U.S. and many American Muslims will be attending Friday prayers. It encouraged communities to increase security in response to the shootings.

“We tell our community, do not be afraid and do not abandon your mosques. Not now, not ever. They want you to be afraid. You should not be afraid. You should be protected,” Awad said.

CAIR also asked that people refrain from sharing the “hate-filled” video and images the suspect posted online.